Keep getting this error code for Windows Defender which says i shud reboot or go to Help and Support to set up manually. No way to reboot and Help and Support gives no help either. Tried Startup, run, appwiz.cpl which gave me a lst of programs so i could uninstall Defender and reinstall it again..... Only problem is that it isn't on the list. Tried downloading from Microsoft Website (the only version they have is almost two years old) but download refused because it is already installed on Windows Vista. So does anyone else have this problem and have resolved it. Would appreciate any feedback. thanks !!!

It is gonna be a pain, short of reinstall.

http://support.microsoft.com/kb/931849

In a nutshell:

*To resolve this problem, follow these steps:

1. Uninstall Windows Defender, and then reinstall Windows Defender. To do this, follow these steps:
1. Click Start, click Run, type appwiz.cpl, and then click OK.
2. Click Windows Defender, and then click Remove.
3. Follow the prompts to uninstall Windows Defender.
4. To reinstall Windows Defender, visit the following Microsoft Web site:
http://www.microsoft.com/athome/secu...yware/software (http://www.microsoft.com/athome/secu...yware/software)
2. If this issue is not resolved after you complete step 1, uninstall Windows Defender, use the Windows Installer CleanUp utility, and then reinstall Windows Defender. To do this, follow these steps:
1. Click Start, click Run, type appwiz.cpl, and then click OK.
2. Click Windows Defender, and then click Remove.
3. Follow the prompts to uninstall Windows Defender.
4. To use the Windows Installer CleanUp utility, click the following article number to view the article in the Microsoft Knowledge Base:
290301 (http://support.microsoft.com/kb/290301/ ) Description of the Windows Installer CleanUp utility
5. To reinstall Windows Defender, visit the following Microsoft Web site:
http://www.microsoft.com/athome/secu...yware/software (http://www.microsoft.com/athome/secu...yware/software)
3. If this issue is not resolved after you complete step 2, follow this step:
1. Click Start, click Run, type regsvr32 file name, and then click OK.

Note In this step, file name is a placeholder for the following files.

Repeat this procedure for the following files:
* wuapi.dll
* wuaueng.dll
* wucltui.dll
* wups.dll
* wuweb.dll
* atl.dll
* softpub.dll
* wintrust.dll
* initpki.dll
* mssip32.dll"

cheers ...

I've found at last the solution for this error code :
Go to Windows Help and Support. Type : Services : and Search,
this will direct you to the Task Manager and just follow the instructions. Have to be careful though as it seems to be unchartered territory. But from there you can start Windows Defender manually, but follow the instructions and you^ll be able to
set it up so it runs automatically.
thanks qhn for your reply but it doesnt work your way. and a
download from Microsoft is impossible, if you have Vista.
took me hours to figure this one out